Officials are probing how a 51-year-old highway bridge came to collapse in the Italian port city of Genoa yesterday, killing at least 26 people and injuring 16 others as it sent dozens of vehicles tumbling into a heap of concrete and twisted steel.

The project's expected to generate 3000 jobs during construction and 1000 ongoing jobs, once completed.

A start date has not been set but Crown estimates the work will take five to six years.

"This will be Melbourne's tallest building, and arguably it will be Australia's tallest building," Mr Andrews said.

"But it's not just about height though. The quality of this design outcome, particularly the public realm benefits, the benefits that will be accessible for all Victorians, really mark this out as a very special project."